Pictorial rehearsal

Subjects were presented with a sequence of picture-word items. The pictures were line drawings of common objects, and the words were the names of the objects. Half of the items were followed quickly by the next item, and the other half by a 15-sec “rehearsal interval.” The subjects were told to use these intervals to rehearse the item just presented, either by saying the word over and over to themselves or by maintaining the picture before the mind’s eye. There followed a test in which each item from the study list was cued with a fragment of either the picture or the name. Consistent with previous findings, identification was more probable for fragments of items that had been followed by a rehearsal interval. In addition, this advantage was found to be greater when the type of cue matched the mode of rehearsal that the subject had been instructed to adopt; there was in fact little, if any, advantage of rehearsal when cue and mode of rehearsal mismatched. This pattern of results suggests functionally distinct pictorial and verbal modes of rehearsal that serve not only to maintain information in conscious mind but also to build up memory proper.     

Agreement between observers when the categories are not specified in advance

To test the agreement between two observers who categorize a number of objects when the categories have not been specified in advance, Brennan & Light (1974) developed a statistic A′ and suggested a normal approximation for its distribution. In this paper it is shown that this approximation is inadequate particularly when one, or both, of the observers place a fairly equal number of objects in all of their categories. A chi-squared approximation to the distribution of A′ is developed and is shown to work well in a variety of situations. The relative powers of A′ and the ordinary X² test for association are dependent on the type of ‘agreement between the observers’ that is assumed. However a simulation for a fairly general type of agreement indicates that the X² test is more powerful. As the X² test is also much easier to apply, it would seem preferable in most situations.